Mixing device



c. A. Manuf-'FEE Er AL 2,184,225

MIXING DEVICE Filed June 2, 1938 Sheets-Sheet 1 mml Ill n ...imI

ec. l, w39. c. A. MCDUFFEE sr AL 2,184,225

MIXING DEvIcE Filed June 2, 195s 2 sheets-sheet 2 lll Patented Dec. 19,1939 Ni'iED STATES MIXING DEVICE Application June 2, 1938, Serial No.211,454

2 Claims.

This invention relates to mixing apparatus, and more particularly to animproved agitator and mixing bowl .which may be used with standardmixing machines.

The primary object of the invention is to provide improved apparatus forthoroughly mixing or kneading the contents of a mixing bowl in a uniformmanner.

Many excellent mixing devices are in commercial use but considerabledifficulty is encountered in obtaining uniform results under identicalmechanical conditions, working on identical material. rIhis isparticularly noticeable where the material to be mixed has a heavyconsistency, such as bread dough, because the dough has a tendency towad and crawl up on the agitator so that the kneading action of themachine is greatly reduced. In scientific laboratory work it isimportant, in developing recipes and the like, that the mechanicaloperation be uniform and standard so that accurate comparisons can bemade of various fleurs, shortening, and the like.

A further object of the invention is to provide a strong, simple, andinexpensive agitator and mixing bowl that will permit the material to beremoved easily after a mixing operation and also permit the apparatus tobe cleaned easily.

In order to accomplish the purpose of the invention it has been founddesirable to provide a fixed stud or linger in the bowl which cooperateswith the moving arms of the agitator, the latter arms being disposed ina definite relation to the stud and side Wall o the bowl. That is, forthe best results there should be sufficient clearance that a kneadingaction is performed, as distinguishcd from a shearing action, on thematerial.

The invention is illustrated in a preferred embodiment in theaccompanying drawings, in which:

Figure l is a side elevational View of a mixing machine provided withthe improved agitator and mixing bowl; Fig. 2 is a broken verticalsectional View ci the mixing bowl showing the agitator in operativeposition, taken as indicated at line i of Fig. 3; Fig. 3 is a plan Viewof the mixing bowl showing in dotted lines some of the various positionsassumed by the agitator in a cycle of operations; and Fig. fi is afragmentary View of the planetary drive.

in the embodiment illustrated, A designates the main frame of themaci'iine provided with a pianetary driving gear A which is driven by asuitable transmission A2 from an electric motor A3; B, a mixing bowlprovided with a water jacket B'; and C, a U-shaped agitator.

The main frame A, planetary gearing A', speed control transmission A2,and driving motor A3, are all of well-known construction. The machineillustrated is known on the market as a C-lO Hobart mixer. The machinehas a special supporting bracket 5 in which the mixing bowl may bedetachably mounted and is arranged so that the bowl may be raised andlowered from operative position to facilitate handling. i

The planetary drive mechanism A' is enclosed by a housing 5 from which ashaft l depends and to which the agitator may be detachably connected.Within the housing A is a pinion gear 8 which is rotated bodily aroundthe center of the mixing bowl and the gear is held in mesh with aplanetary gear 9 which causes the agitator arms to make about threerevolutions each time the pinion gear rotates around within theplanetary gear.

The mixing bowl is an open top, round, cylindrical container having abottom wall lil. The bowl is provided with suitable arms I l which aregripped by the bracket 5 on the mixing machine. Preferably the lowerportion of the bowl is provided with a water jacket B' having an inletconduit l2 and an outlet conduit i3 to which hoses may be attached tocirculate cooling water or heating water to maintain a desiredtemperature within the bowl. An axially disposed stud I4 is xed to thebottom Wall of the bowl and is designed to cooperate with the agitatorin its mixing operation. The lower end of the stud is shown with aprojection l5 which passes through the bottom of the water cooler andgrips the latter in position by means of a nut it. Preferably, the studM extends up to about the center of the bowl.

The agitator C is attached to the shaft l by means of a hollow shank llprovided with bayonet slots i8 which cooperate with pins i9 on saidshaft. The agitator has a pair of parallel downwardly extending arms 2liwhich are integrally formed with a cross-bar 2| secured to the shank il.The arms 2t and stud Ul are of the same diameter and have a circularcross-section. In the embodiment illustrated, the bowl has an insidediameter of about seven and one-fourth inches and the stud lli has adiameter of sevensixteenths of an inch and is preferably made of a mildsteel. For larger bowls the agitator and stud may be modiiied in size.

It may be noted that the arms 20 are separated by a greater distancethan the radius of the bowl so that the arms 20 rotate eccentrcallyabout the stud I4. A clearance between the stud lll and the arms 20 andalso between the arms 2l) and the side Walls of the bowl is sufcient toproduce a kneading action on the material rather than a shearing action.This clearance is a little less than half the diameter of the stud.

To operate the device the materials to be mixed are placed in the bowland the bowl mounted in the bracket 5 which is adapted to raise it intothe operative position shown in Figs. 1 and 2. The motor is then startedand permitted to run a denite length of time and drive the agitator atthe proper speed through regulationof the transmission A2. Excellentresults are thus obtained and it has been found that the dough will notclimb up the arms 20 and cling to the cross-bar 2l or shank I1 andthereby escape the mixing operation.

By using the same type of equipment under the same operating conditions,which are fully controllable, standard results are obtained inlaboratories in various parts of the country and products may beaccurately and scientically compared.

The foregoing detailed description has been given for clearness ofunderstanding only, and no unnecessary limitations should be understoodtherefrom, but the appended claims should be construed as broadly aspermissible, in View of the prior art.

We claim:

l. In a dough mixing device of the character set forth: a verticallydisposed cylindrical mixing bowl having one centrally disposed roundstud extending up near to the center of the bowl; a single U-shapedagitator journalled above said bowl and having parallel round armsdisposed so as to rotate eccentrically about said stud; and drivingmeans for moving said agitator bodily around the stud while rotating thearms with respect to said stud.

2. A device as specified in claim l, in which the stud and arms of theagitator have substantially equal diameters, and the arms of theagitator are spaced apart so that during rotation they will clear saidstud and the cylindrical side walls of the bowl by a distance equal toabout half the diameter of the stud.

CLAUDE A. MCDUFFEE. TAYLOR W. CREECH.

